1. Field of the Invention
The present invention generally relates to optics and colorimetry and, in particular, relates to a reflectance sensor having particular optical dye thicknesses for deposited filters that are designed through the use of varying densities of a controlled set of dyes, such that, when weighted by a colorimeter illuminant-spectrum, the deposited filters approximate Commission Internationale de l'Eclairage (CIE) color-matching functions, weighted by a reference illuminant spectrum.
2. Description of the Related Art
Colorimeters that measure reflective or transmissive colors with the same spectral sensitivities as the human visual system use composite parts that have negative impacts on cost, assembly, mechanical robustness, and optical efficiency. For example, conventional reflective- and transmissive-mode colorimeters deploy multiple light emitting diode (LED) light sources and a single detector. By use of such multiple light sources conventional colorimeters determine the tristimulus values of a reflective sample as they would appear under a selected light source (e.g., CIE standard illuminant D50 or D65). However, the multiplicity of light sources has economic and engineering disadvantages.